Answer:
Your future connection with Britain, whom you can neither love nor honor, will be forced and unnatural, and being formed only on the plan of present convenience, will in a little time fall into a relapse more wretched than the first
Paine shows that it will not be possible especially for those who have lost homes, parent or child. Or if wife or child has been left destitute.
His reasoning was effective because in the end he said "let us come to a final separation, and not leave the next generation to be cutting throats, under the violated unmeaning names of parent and child.…
You would write it in the casual form. You wouldn't write it informal because it would sound too unprofessional. And making it formal, well, some people wouldn't understand if you were to write in the formal way. They wouldn't understand the words. So just the casual way would do.
Theme is the overall message, while topic is the subject being discussed
On my day off, i want to go see a movie, go to the park, and go visit my grandmother